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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Nitrogen-enriched, ordered mesoporous carbons for potential electrochemical energy storage

Zhu, Jinhui, Yang, Jun, Miao, Rongrong, Zhaoquan, Zhaoquan, Zhuang , Xiaodong, Feng, Xinliang 17 July 2017 (has links) (PDF)
Nitrogen-doped (N-doped) porous carbons have drawn increasing attention due to their high activity for electrochemical catalysis, and high capacity for lithium-ion (Li-ion) batteries and supercapacitors. So far, the controlled synthesis of N-enriched ordered mesoporous carbons (N-OMCs) for Li-ion batteries is rarely reported due to the lack of a reliable nitrogen-doping protocol that maintains the ordered mesoporous structure. In order to realize this, in this work, ordered mesoporous carbons with controllable N contents were successfully prepared by using melamine, F127 and phenolic resin as the N-source, template and carbon-source respectively via a solvent-free ball-milling method. The as-prepared N-OMCs which showed a high N content up to 31.7 wt% were used as anodes for Li-ion batteries. Remarkably, the N-OMCs with an N content of 24.4 wt% exhibit the highest reversible capacity (506 mA h g−1) even after 300 cycles at 300 mA g−1 and a capacity retention of 103.3%. N-OMCs were also used as electrode materials in supercapacitors and a capacity of 150 F g−1 at 0.2 A g−1 with stable cycling up to 2500 times at 1 A g−1 was achieved. These attractive results encourage the design and synthesis of high heteroatom content ordered porous carbons for applications in the field of energy storage and conversion.
2

Nitrogen-enriched, ordered mesoporous carbons for potential electrochemical energy storage

Zhu, Jinhui, Yang, Jun, Miao, Rongrong, Zhaoquan, Zhaoquan, Zhuang, Xiaodong, Feng, Xinliang 17 July 2017 (has links)
Nitrogen-doped (N-doped) porous carbons have drawn increasing attention due to their high activity for electrochemical catalysis, and high capacity for lithium-ion (Li-ion) batteries and supercapacitors. So far, the controlled synthesis of N-enriched ordered mesoporous carbons (N-OMCs) for Li-ion batteries is rarely reported due to the lack of a reliable nitrogen-doping protocol that maintains the ordered mesoporous structure. In order to realize this, in this work, ordered mesoporous carbons with controllable N contents were successfully prepared by using melamine, F127 and phenolic resin as the N-source, template and carbon-source respectively via a solvent-free ball-milling method. The as-prepared N-OMCs which showed a high N content up to 31.7 wt% were used as anodes for Li-ion batteries. Remarkably, the N-OMCs with an N content of 24.4 wt% exhibit the highest reversible capacity (506 mA h g−1) even after 300 cycles at 300 mA g−1 and a capacity retention of 103.3%. N-OMCs were also used as electrode materials in supercapacitors and a capacity of 150 F g−1 at 0.2 A g−1 with stable cycling up to 2500 times at 1 A g−1 was achieved. These attractive results encourage the design and synthesis of high heteroatom content ordered porous carbons for applications in the field of energy storage and conversion.
3

Bipolar nitrogen-doped graphene frameworks as high-performance cathodes for lithium ion batteries

Huang, Yanshan, Wu, Dongqing, Dianat, Arezoo, Bobeth, Manferd, Huang, Tao, Mai, Yiyong, Zhang, Fan, Cuniberti, Gianaurelio, Feng, Xinliang 17 July 2017 (has links) (PDF)
Hierarchically porous nitrogen-doped graphene frameworks (N-GFs) are fabricated through the ice-templating of GO with polyethylenimine and the thermal treatment of the resultant hybrids. As cathode materials in lithium ion batteries (LIBs), the obtained N-GFs exhibit an outstanding specific capacity of 379 mA h g−1 at 0.5 A g−1 for 2500 cycles. Even at an ultrahigh current density of 5 A g−1, the N-GFs maintain a capacity of 94 mA h g−1, superior to that of most reported LIB cathode materials. The experimental results and quantum mechanics calculations suggest that pyridinic-like N and pyridinic N-oxide in graphene are responsible for the excellent cathodic performance of the bipolar N-GFs by providing fast surface faradaic reactions with both p- and n-doped states.
4

Bipolar nitrogen-doped graphene frameworks as high-performance cathodes for lithium ion batteries

Huang, Yanshan, Wu, Dongqing, Dianat, Arezoo, Bobeth, Manferd, Huang, Tao, Mai, Yiyong, Zhang, Fan, Cuniberti, Gianaurelio, Feng, Xinliang 17 July 2017 (has links)
Hierarchically porous nitrogen-doped graphene frameworks (N-GFs) are fabricated through the ice-templating of GO with polyethylenimine and the thermal treatment of the resultant hybrids. As cathode materials in lithium ion batteries (LIBs), the obtained N-GFs exhibit an outstanding specific capacity of 379 mA h g−1 at 0.5 A g−1 for 2500 cycles. Even at an ultrahigh current density of 5 A g−1, the N-GFs maintain a capacity of 94 mA h g−1, superior to that of most reported LIB cathode materials. The experimental results and quantum mechanics calculations suggest that pyridinic-like N and pyridinic N-oxide in graphene are responsible for the excellent cathodic performance of the bipolar N-GFs by providing fast surface faradaic reactions with both p- and n-doped states.

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